But my comment about the other pilot involved being left free to do a the same again should no, in my opinion, have let off without a safety check flight.
I think we are going to have to disagree on this one as I just see you trying to transfer some of the blame.
In my view he was having a safety check with you! It was you who failed him by not taking your responsibility as an Instructor and commander of the flight seriously. I would suspect that he has probably learnt something from your mistake anyway!